Puppet master digest issues

Question

I am running the following setup of Puppet :

• Puppet master : CentOS 6.4 x86_64 with puppet-server-3.2.1-2.2 and openssl-1.0.0-27.el6_4.2.x86_64
• Puppet agent 1 : RedHat AS 4.8 x86 with puppet-0.25.6-1.el4 and openssl-0.9.7a-43.20.el4
• Puppet agent 2 : RHEL 5.10 x86 with puppet-2.6.18-3.el5 and openssl-0.9.8e-26.el5_9.1

I noticed that my RedHat 4 agent cannot connect to my Puppet master and I think the reason is because the version of the libssl packaged with RH4 (0.9.7a-43.20 in my case) cannot manage the digests generated by the Puppet server.

The tests I performed :

• From a non-working RedHat 4 agent (with OpenSSL v0.9.7a-43.20.el4) :

# openssl s_client -host puppetmaster.test.lan -port 8140 -cert /etc/puppet/ssl/certs/rh4as.test.lan.pem -key /etc/puppet/ssl/private_keys/rh4as.test.lan.pem -CAfile /etc/puppet/ssl/certs/ca.pem 
CONNECTED(00000003)
depth=1 /CN=Puppet CA: puppetmaster.test.lan
verify return:1
depth=0 /CN=puppetmaster.test.lan
verify error:num=7:certificate signature failure
verify return:1
depth=0 /CN=puppetmaster.test.lan
verify return:1
---
Certificate chain
 0 s:/CN=puppetmaster.test.lan
   i:/CN=Puppet CA: puppetmaster.test.lan
 1 s:/CN=Puppet CA: puppetmaster.test.lan
   i:/CN=Puppet CA: puppetmaster.test.lan
---
Server certificate
-----BEGIN CERTIFICATE-----
[...]
-----END CERTIFICATE-----
subject=/CN=puppetmaster.test.lan
issuer=/CN=Puppet CA: puppetmaster.test.lan
---
No client certificate CA names sent
---
SSL handshake has read 3793 bytes and written 2853 bytes
---
New, TLSv1/SSLv3, Cipher is DHE-RSA-AES256-SHA
Server public key is 4096 bit
Secure Renegotiation IS supported
SSL-Session:
Protocol  : TLSv1
Cipher    : DHE-RSA-AES256-SHA
Session-ID: 8B8607495273640FB4BCB80C5C1CE261FED1633CA112C1D216BE187EDEA81F77
Session-ID-ctx: 
Master-Key: A2A3AC5B0679C27FFE070D0B3154233EC4D0F17310148AE7B6FF502A7DB95679D33BB097C0ED89AE67AA42E95BD4D952
Key-Arg   : None
Krb5 Principal: None
Start Time: 1392216496
Timeout   : 300 (sec)
Verify return code: 7 (certificate signature failure)
---
closed

• From a working RedHat 5 agent (with OpenSSL v0.9.8e-26.el5_9.1) :

# openssl s_client -host puppetmaster.test.lan -port 8140 -cert /etc/puppet/ssl/certs/rhel5.test.lan.pem -key /etc/puppet/ssl/private_keys/rhel5.test.lan.pem -CAfile /etc/puppet/ssl/certs/ca.pem
CONNECTED(00000003)
depth=1 /CN=Puppet CA: puppetmaster.test.lan
verify return:1
depth=0 /CN=puppetmaster.test.lan
verify return:1
---
Certificate chain
 0 s:/CN=puppetmaster.test.lan
   i:/CN=Puppet CA: puppetmaster.test.lan
 1 s:/CN=Puppet CA: puppetmaster.test.lan
   i:/CN=Puppet CA: puppetmaster.test.lan
---
Server certificate
-----BEGIN CERTIFICATE-----
[...]
-----END CERTIFICATE-----
subject=/CN=puppetmaster.test.lan
issuer=/CN=Puppet CA: puppetmaster.test.lan
---
No client certificate CA names sent
---
SSL handshake has read 3793 bytes and written 2831 bytes
---
New, TLSv1/SSLv3, Cipher is DHE-RSA-AES256-SHA
Server public key is 4096 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
SSL-Session:
Protocol  : TLSv1
Cipher    : DHE-RSA-AES256-SHA
Session-ID: 7B70B803D8D0FFC65F2696D337EB40CDE41D188F9F1BA1D7FE416DA326B49AFD
Session-ID-ctx: 
Master-Key: BE57138CA99AA4AA59769B3E8396E9C25594264E196FB50DB066679EA569311521F1BBBCD25962B780A38D95A3AD9346
Key-Arg   : None
Krb5 Principal: None
Start Time: 1392224552
Timeout   : 300 (sec)
Verify return code: 0 (ok)
---
closed

• From the Puppet master :

# puppet cert --list --all
+ "rh4as.test.lan"      (SHA256) 69:BD:D9:B6:31:6B:3E:90:9B:5E:1B:90:FA:24:08:1A:48:31:B1:17:65:DF:93:26:70:29:5A:C3:3E:C8:0F:7E
+ "rhel5.test.lan"      (SHA256) 83:58:A9:25:7C:9A:41:C9:A7:7E:45:26:40:EE:D0:05:9A:31:6E:8D:15:CE:57:86:0C:DA:E0:D0:2A:9C:B3:DB
+ "puppetmaster.test.lan" (SHA256) 9C:AC:8E:CA:71:24:2B:BB:61:52:01:4F:F1:DF:BD:B6:25:6C:DA:61:44:E4:1E:71:77:DF:2F:BA:AE:A9:40:FD (alt names: "DNS:puppet", "DNS:puppet.test.lan", "DNS:puppetmaster.test.lan", "DNS:puppetmaster")

Additional tests :

• I made sure all the servers are correctly synchronized with the NTP server
• I deleted all local certificates on the RH4AS agent and reissued them
• I deleted local references to the RH4AS agent on the Puppet master
• I installed from source Puppet agent v2.6.0 on the RH4AS server but had the same issue

I read these links :

• http://projects.puppetlabs.com/issues/17295
• https://groups.google.com/forum/#!msg/puppet-dev/_jkdY1Hmq6U/X0gj7NSgK64J
• Puppet's automatically generated certificates failing

and I realized I had 2 options :

• upgrade my OpenSSL version to +0.9.8 (1.0.0 to be safe)
• downgrade the digest used by the Puppet master from SHA256 to SHA1 (or maybe even MD5)

Unfortunately, option #1 (upgrade OpenSSL) is not applicable in my environment. So I guess I'm stuck with downgrading the digest used by the Puppet master. But I can't find an option in the whole man puppet.conf that could be used towards this goal. I tried to play with the keylength parameter but to no avail.

If anybody can help me on this issue, I would really appreciate.

Thanks in advance to all.

Answer 1

I ended up downgrading my Puppet Master version from the 3.x branch to 2.7.x (as indicated in this post : https://groups.google.com/forum/#!msg/puppet-dev/_jkdY1Hmq6U/QJ6nHP2ORtYJ).

But I consider as probably valid the answer of sciurus, as I was told by Puppet devs that I could work around this issue by setting up a SHA1-compliant CA.

Answer 2

It looks like you have the problem discussed at Feature #21029: Allow control over the digest used to create CA certificates. It seems like a workaround for this will not be implemented in puppet, and so you need to create the certificates manually with OpenSSL.